Gunmen stormed the headquarters of Libya’s national oil company in Tripoli on Monday, setting off explosions, taking hostages and spraying gunfire, leaving several people dead or wounded before forces aligned with the government took control of the building. The identity and motives of the assailants were not clear.
The oil company said two of its employees had been killed, and there were reports of two gunmen killed, putting the total number of dead at four. But an employee who escaped the assault said he believed that as many as six people had been killed, including three of the assailants.
The attack follows a month of escalating violence among rival militias competing for control of Tripoli, the capital, where a United Nations-backed government has its headquarters but remains largely powerless. Last week, clashes killed more than 60 people.
Any attack on the national oil company is significant because petroleum is the lifeblood of the Libyan economy, and competition for control of the country’s vast oil reserves is at the heart of the often violent struggle for power there. Cuts in oil revenue because of the fighting have driven Libya into a severe financial crisis, with the government failing to meet the public payrolls, long lines forming at banks, and inflation soaring.
The employee who escaped, Baha Elddin, said in an interview that six men armed with “machine guns” had fought their way into the building. Three had blown themselves up, he said, and three others had climbed the stairs to the upper floors.
Mr. Elddin said that local militia fighters had responded to the incursion by besieging the building and that their gunfire may have caused the most casualties. “They started shooting at the assailants inside while the assailants threw grenades down on them from the second floor,” Mr. Elddin said in a telephone interview. “I think that most injuries happened because the respondents were shooting in.”
On Facebook, a government-aligned militia described the assault as a “terrorist attack” and the assailants as “suicide bombers.”
Speaking in the early afternoon in Tripoli, Mr. Elddin said that the battle had ended with as many as 10 employees injured, and that it was unclear whether the three assailants who had climbed the stairs had escaped from the scene. He and the militia both described the attackers as dark-skinned, suggesting they could be from ethnic groups native to Libya or from other African countries.
There was no immediate claim of responsibility for the attack.
The chairman of the state oil company, Mustafa Sanallah, escaped unharmed, and experts said it was unlikely that the attack would directly affect Libya’s oil production. But the events demonstrated that the country’s oil infrastructure remains vulnerable.
“It’s a reminder that the country remains at risk,” said Riccardo Fabiani, a geopolitical analyst at Energy Aspects, a market research firm. “There is still a backdrop of violence and instability that could again cut production at anytime in the future.”
Libya has descended into chaos in the seven years since the overthrow of Col. Muammar el-Qaddafi. The United Nations and Western powers have tried to set up a government based in Tripoli that might be able to unify the country.
But so far, power in Tripoli and Western Libya remains divided among rival local or Islamist militias. A would-be strongman, Gen. Khalifa Hifter, dominates the Eastern area around Benghazi, thanks in part to the backing of Egypt and the United Arab Emirates.
The Islamic State, also known as ISIS or ISIL, had controlled its own beachhead around the coastal city of Sirte until it was driven out by Western airstrikes and local militias in 2016. Many of its fighters have fled into the sparsely populated desert regions. They occasionally stage terrorist attacks on institutions of the rival governments backed by the United Nations and General Hifter, including a similar assault last spring on an election commission.
Several parties agreed in May to hold elections in December for a president and a Parliament. How and by whom that vote might be conducted and secured remains to be determined, and the recent fighting in Tripoli underscores the scale of the challenge.
Analysts say the National Oil Corporation has managed to remain neutral amid the turmoil. It has increased production — which fell to almost nothing after war broke out in 2011 — to around one million barrels a day.
That is still significantly below prewar output, but analysts say that under current circumstances, it is probably close to the maximum Libya can produce. Oil producing centers, pipelines and export terminals around the country are vulnerable to attack.
Monday’s assault comes at a time of growing concerns about global oil supplies. As the Trump administration tries to cut off Iranian exports, they have declined to around two million a day in August from about 2.7 million barrels a day in May, and they are expected to drop to 1.5 million a day in September, according to Energy Aspects. Venezuela’s output continues to decline amid political chaos and economic collapse.
“Too many market participants are way too complacent about Libya,” said Helima Croft, an analyst at RBC Capital Markets in New York.
“We are one major supply outage away from a super spike,” she added, referring to much higher prices.
Stanley Reed contributed reporting.
